As a system using communication service such as wireless LAN, LTE, ZigBee (registered trademark), and Bluetooth (registered trademark), an M2M (Machine to Machine) system is known. In the M2M system, devices mounted with wireless machines exchange information to each other without people, so that the devices are automatically controlled.
As one example of the M2M system, for example, Patent Literature 1 (Japanese Patent Publication No. 4237134) discloses the following technique. That is to say, it is a network system constituted so that a mobile communication network having a wireless terminal, a gateway node capable of wireless communication with the wireless terminal and a position information storage device for holding position information of the wireless terminal is connected with another network to be connected with a terminal which is a transmission destination of a message from the wireless terminal via a gateway. The network system has terminal address holding means for holding an address of the terminal as the transmission destination predetermined for each wireless terminal. When a message is transmitted from the wireless terminal to the terminal, the gateway node receives a wireless frame from the wireless terminal and accesses to the terminal address holding means so as to specify a terminal address of a transmission destination of the message for each wireless terminal and transmits the message to the terminal of the specified transmission destination via the gateway. When the message is transmitted from the terminal to the wireless terminal, the gateway accesses to the position information storage device so as to obtain position information from ID of the wireless terminal and transmit the message to the corresponding gateway node based on the obtained position information. The gateway node transmits the message to the wireless terminal.